Souza, C. P. de; Jannotti-Passos, L. K.; Ferreira, S. S.; Vieira, I. B. de F. Schistosoma Mansoni: The Sex Ratios of Worms in Animals Infected With Cercariae from Three Species of Biomphalaria . Rev. Inst. Med. Trop. São Paulo 1996, 38 (2), 141-145.